In message , Smolley writes
I have about 60 off 155mm x 2mm cutting discs of the German 'Pferd' Horse
Elastic Brand and they have been in the shed since 1990. They look quite
sound and sound like crockery when pinged, but no ring. The resin is still
very hard. Any thoughts on them being unsafe.....anyone ?

No views about your particular discs but suspect the date warnings might
be health and safety overkill.

In 40 or so years, I have never had any disc fail (9", 5" and 4.5")
other than through extreme misuse. Even then it was only the cutting
edge shredding with any bits contained by the guard.

--
Tim Lamb